As you can see in a thread on the very topic, so far I've not been very impressed with the AI's handling of either the default EB formations, nor DarthMod either when it comes to phalanx armies.

Is Sinhuet's mod any better? Can they hold a line with it? Problem is the AI starts out with it's troops in the right place, then proceeds to march them all over the place and lose any sense of cohesion, making them ridiculously easy to beat in series.